5Doraszelski U. Innovations, Improvements, and the Optimal Adoption of New Technologies[ R]. Working Paper, Hoover Institution, Stanford University, http://pubweb. acns. nwu. edu/- udo390/techadop. pdf, 2002.
6Bessen J. Real Options and the Adoption of New Technologies[ R]. Working Paper, MIT, http://www. researchoninnovation. org/realopt. pdf, 1999.
7Sarkar S. On the investment-uncertainty relationship in a real options model[ J]. Journal of Economic Dynamics and Control, 2000,24(2) : 219-225.
8Cohen W M, Levinthal D A. Innovation and learning: The two faces of R&D[J]. Economics Journal, 1989, 99(397) : 569-596.
10Hoppe H C. Second-mover advantages in the strategic adoption of new technology under uncetlainty[ J]. International Journal of Industrial Organization, 2000, 18(2): 315-338.